Deleting From Camera Roll is also Deleting From Photo Stream

I recently took a slew of photos on my iPhone 5S.
So I went through the photos and deleting several of them from my camera roll.
I was surprise to notice that they were also deleted from my Photo Stream.
Saves me a lot of time since I always try to have my Photo Stream mirror my Camera Roll.

Is this new since the last update or have I just been asleep at the wheel?